Comparison of the In vitro Inhibitory Effects of Doses of Tannin Rich Plant Extracts and Ivermectin on Egg Hatchability, Larvae Development and Adult Mortality of Haemonchus contortus

Abstract

The study report here was undertaken to quantify and compare the in vitro inhibitory effects of doses of tannin rich plant extracts, ivermectin and distil water on egg hatchability, larvae development and adult mortality of Haemonchus contortus. Ficus sychomorus, Phyllanthus sepialis and Rhus glutinosa species suspected with high contents of condensed tannins (CT) were collected from their natural habitat in Omo Nada district of Jimma zone, south western Ethiopia. The leaves of plant species were dried at 55°C to constant weight, ground to 1.5 mm sieve and subjected to CT analysis. Aqueous acetone (70%) was incorporated for the extraction of plant samples. The extracts were prepared to obtain 0.1ml, 0.3ml and 0.5 ml from 50 mg /ml stock solution and accompanied by controls: Ivermectin (positive control) and distill water (negative control). The data were subjected to a two-way analysis of variance following the general linear model procedure of SAS in a 5×3 factorial arrangement. The CT contents of the respective plants were 120, 110 and 188 g/kg DM, respectively. Interspecies variations were significant for CT concentration across the dosage levels (P<0.001). The mean egg inhibition percentage of plant extracts varied from the lowest inhibition effect for P. sepialis (46- 57.33%) to the highest inhibition effect for R. glutinosa (59.67-76%) (P<0.001). The larval development inhibition of ivermectin was not found to be superior compared to tannin rich extracts (P>0.05).The fastest adult motility was observed for different doses of ivermectin and R. glutinosa as compared to other treatment groups (P<0.001). Among plants, the fastest and slowest adult motility rates were recorded for R. glutinosa (1:22h to 0:58h) and P. sepialis (3:00h to 2:50h) (P<0.001). Yet, the effects of negative control didn’t vary in inhibiting egg hatchability, larval development and adult motility (P>0.05). In general, all plants showed anti-H. contortus activity in the three-life cycle of the parasite and it was also associated with the dosage levels and the concentration of CTs contained in the plants. Furthermore, since the anti-Haemochus activity of R. glutinosa was found to be feasible as that of ivermectin, therefore, this plant can be used as alternative anthelmentic for the treatment of Haemonchosis